CVE-2022-40475 is a critical command injection vulnerability identified in the TOTOLINK A860R router firmware version V4.1.2cu.5182_B20201027. The vulnerability exists in the /cgi-bin/downloadFile.cgi component of the device's web interface. Command injection (CWE-78) vulnerabilities allow an attacker to execute arbitrary commands on the underlying operating system with the privileges of the affected application. In this case, the vulnerability is remotely exploitable over the network without requiring any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). This means that an attacker can send specially crafted requests to the vulnerable CGI endpoint and execute arbitrary system commands, potentially taking full control of the device. The CVSS score of 9.8 (critical) reflects the high impact on confidentiality, integrity, and availability, as successful exploitation can lead to complete compromise of the router, including interception or manipulation of network traffic, installation of persistent malware, or use of the device as a pivot point for further attacks within the network. No patches or vendor mitigations are currently listed, which increases the urgency for affected users to take protective measures. The vulnerability was published on September 29, 2022, and although no known exploits in the wild have been reported yet, the severity and ease of exploitation make it a significant threat to networks using this router model.

For European organizations, this vulnerability poses a substantial risk, especially for small and medium enterprises or home offices that rely on TOTOLINK A860R routers for internet connectivity. Exploitation could lead to unauthorized access to internal networks, data interception, and disruption of services. Given the router's role as a gateway device, compromise could allow attackers to bypass perimeter defenses, conduct man-in-the-middle attacks, or launch further intrusions into corporate networks. The impact extends to confidentiality breaches of sensitive data, integrity violations through manipulation of network traffic, and availability disruptions by rendering the router or network unusable. Additionally, compromised routers could be conscripted into botnets, amplifying broader cyber threats. The lack of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of exploitation if vulnerable devices are exposed to the internet or accessible from less secure network segments.

Immediate mitigation steps include isolating the vulnerable TOTOLINK A860R routers from untrusted networks, especially the internet, to prevent remote exploitation. Network administrators should implement strict firewall rules to block access to the /cgi-bin/downloadFile.cgi endpoint or restrict management interfaces to trusted IP addresses only. Monitoring network traffic for unusual requests targeting the CGI endpoint can help detect attempted exploitation. If possible, replace the affected router with a model from a vendor that provides timely security updates. In the absence of official patches, applying network segmentation to limit the router's access to critical assets reduces potential damage. Users should also disable remote management features if enabled and change default credentials to strong, unique passwords to reduce attack surface. Regularly checking for firmware updates from TOTOLINK and applying them promptly once available is essential. Additionally, organizations should conduct vulnerability scans to identify affected devices and prioritize remediation efforts accordingly.